UPDATES
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
phenylpalladation of 3a on its si-face will lead to the References
product 5am with S configuration. The coordination
with re-face would suffer from a serious steric
repulsion caused by the pentamethylphenyl ring and
the sulfonyl group.
In summary, a series of amino acid-derived
phosphine-imine ligands were designed and synthe-
sized for palladium-catalyzed arylation of cyclic N-
sulfonyl imines. The easily prepared phosphine-imine
ligands demonstrated high catalytic activities and
useful level of enantioselectivities.
[1] For reviews on the transition metal-catalyzed asymmet-
ric addition of organometallic reagents to imines, see:
a) S. Kobayashi, Y. Mori, J. S. Fossey, M. M. Salter,
Chem. Rev. 2011, 111, 2626; b) C. S. Marques, A. J.
Burke, ChemCatChem 2011, 3, 635; c) K. Yamada, K.
Tomioka, Chem. Rev. 2008, 108, 2874; d) G. K. Friestad,
A. K. Mathies, Tetrahedron 2007, 63, 2541.
[
2] Selected examples on asymmetric addition of organo-
boron reagents to acyclic imines. For Rh catalysis, see:
a) M. Kuriyama, T. Soeta, X. Hao, Q. Chen, K.
Tomioka, J. Am. Chem. Soc. 2004, 126, 8128; b) N.
Tokunaga, Y. Otomaru, K. Okamoto, K. Ueyama, R.
Shintani, T. Hayashi, J. Am. Chem. Soc. 2004, 126,
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
Experimental Section
Synthesis of Amino Acid-Derived Phosphine-Imine
1
3584; c) D. J. Weix, Y. Shi, J. A. Ellman, J. Am. Chem.
Ligands 2a–2l and PdCl (2l) Complex
2
Soc. 2005, 127, 1092; d) Y. Otomaru, A. Kina, R.
Shintani, T. Hayashi, Tetrahedron: Asymmetry 2005, 16,
[10b]
A modified procedure based on Morimoto’s report
for
1
673; e) H.-F. Duan, Y.-X. Jia, L.-X. Wang, Q.-L. Zhou,
synthesis of phosphine-imine ligands: A 25 mL flask was
charged with b-aminoalkylphosphine (0.30 mmol) and alde-
hyde (0.36 mmol) in toluene (15.0 mL). The mixture was
heated at reflux for 4 h under argon with Dean-Stark trap.
The solvent was removed under vacuum. The crude mixture
was subjected to a short silica gel column with hexane/ethyl
acetate (25:1) to give crude product (the column was
Org. Lett. 2006, 8, 2567; f) R. B. C. Jagt, P. Y. Toullec, D.
Geerdink, J. G. de Vries, B. L. Feringa, A. J. Minnaard,
Angew. Chem. Int. Ed. 2006, 45, 2789; Angew. Chem.
2006, 118, 2855; g) Z.-Q. Wang, C.-G. Feng, M.-H. Xu,
G.-Q. Lin, J. Am. Chem. Soc. 2007, 129, 5336; h) R.
Shintani, M. Takeda, T. Tsuji, T. Hayashi, J. Am. Chem.
Soc. 2010, 132, 13168; i) H.-Y. Yang, M.-H. Xu, Chem.
Commun. 2010, 46, 9223; j) Y. Luo, A. J. Carnell,
Angew. Chem. Int. Ed. 2010, 49, 2750; Angew. Chem.
pretreated with 5% Et N in hexane, and then flushed with
3
hexane). The crude product was heated to 2008C under
vacuum to remove excess aldehyde, and gave pure product.
2
010, 122, 2810; k) C.-C. Chen, B. Gopula, J.-F. Syu, J.-
A 25 mL round bottle flask was charged with PdCl (PhCN)
2
2
H. Pan, T.-S. Kuo, P.-Y. Wu, J. P. Henschke, H.-L. Wu, J.
Org. Chem. 2014, 79, 8077; For Pd catalysis, see: l) H.
Dai, M. Yang, X. Lu, Adv. Synth. Catal. 2008, 350, 249;
m) H. Dai, X. Lu, Tetrahedron Lett. 2009, 50, 3478;
n) G.-N. Ma, T. Zhang, M. Shi, Org. Lett. 2009, 11, 875;
o) C. S. Marques, A. J. Burke, Eur. J. Org. Chem. 2010,
(1.00 mmol, 383.6 mg) in acetone (5.0 mL) under argon.
Phosphine-imine ligand 2l (1.00 mmol, 443.6 mg) in acetone
(10.0 mL) was added slowly over 5 min at room temperature.
The mixture was stirred at room temperature for 2 h, in the
meantime yellow precipitates were formed. The mixture was
concentrated to 5 mL, and filtrated. The residue was washed
with hexane (10 mL 3 3), and dried under vacuum to give
1
639; p) J. Chen, X. Lu, W. Lou, Y. Ye, H. Jiang, W.
Zeng, J. Org. Chem. 2012, 77, 8541; q) X. Gao, B. Wu,
Y. Zhong, Y.-G. Zhou, Org. Biomol. Chem. 2016, 14, 55;
r) Q. He, L. Wu, X. Kou, N. Butt, G. Yang, W. Zhang,
Org. Lett. 2016, 18, 288.
pure product PdCl (2l) (528.0 mg, 85% yield) as yellow
2
solid.
General Procedure for Asymmetric
Palladium-Catalyzed Arylation Reactions
[3] Selected examples on asymmetric addition of organo-
boron reagents to cyclic imines. For Rh catalysis, see:
a) T. Nishimura, A. Noishiki, G. C. Tsui, T. Hayashi, J.
Am. Chem. Soc. 2012, 134, 5056; b) Y. Luo, A. J.
Carnell, H. W. Lam, Angew. Chem. Int. Ed. 2012, 51,
PdCl (2l) (6.2 mg, 0.01 mmol), N-sulfonyl imine (0.20 mmol),
2
and boronic acid (0.40 mmol) were placed in a Schlenk tube.
To the tube, 1,2-dichloroethane (1.0 mL) was added, and
then AgBF4 (5.8 mg, 0.03 mmol) in 1,2-dichloroethane
(1.0 mL) was added. The mixture was stirred at 658C for 1 h,
and it was directly subjected to flash chromatography on
silica gel using hexane/ethyl acetate as an eluent to give pure
product.
6
762; Angew. Chem. 2012, 124, 6866; c) Y. Luo, H. B.
Hepburn, N. Chotsaeng, H. W. Lam, Angew. Chem. Int.
Ed. 2012, 51, 8309; Angew. Chem. 2012, 124, 8434; d) T.
Nishimura, Y. Ebe, H. Fujimoto, T. Hayashi, Chem.
Commun. 2013, 49, 5504; e) T. Nishimura, A. Noishiki,
Y. Ebe, T. Hayashi, Angew. Chem. Int. Ed. 2013, 52,
1
777; Angew. Chem. 2013, 125, 1821; f) H. Wang, M.-H.
Acknowledgements
We thank the National University of Singapore (R-143-000-
Xu, Synthesis 2013, 45, 2125; g) Y.-J. Chen, Y.-H. Chen,
C.-G. Feng, G.-Q. Lin, Org. Lett. 2014, 16, 3400; h) H.
Wang, Y. Li, M.-H. Xu, Org. Lett. 2014, 16, 3962; i) J.
Kong, M. McLaughlin, K. Belyk, R. Mondschein, Org.
Lett. 2015, 17, 5520; j) T. Jiang, Z. Wang, M.-H. Xu,
Org. Lett. 2015, 17, 528; k) R. Takechi, T. Nishimura,
Org. Biomol. Chem. 2015, 13, 4918; l) Y. Li, Y.-N. Yu,
M.-H. Xu, ACS Catal. 2016, 6, 661.
599-112) for generous financial support.
Adv. Synth. Catal. 2017, 359, 1–8
6
ꢁ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!